EXHIBIT A.12
`U.S. Patent No. 7,147,759
`
`References cited herein:
`
`(cid:120) U.S. Patent No. 7,147,759 (“‘759 Patent”)
`
`(cid:120) U.S. Pat. No. 6,413,382 (“Wang”)
`
`(cid:120) A. A. Kudryavtsev, et al, Ionization relaxation in a plasma produced by a pulsed inert-gas
`discharge, Sov. Phys. Tech. Phys. 28(1), January 1983 (“Kudryavtsev”)
`
`(cid:120) EP 1 113 088 (“Yamaguchi”)
`
`Claim 38
`
`[20pre.] A method
`of generating
`sputtering flux, the
`method comprising:
`
`[20a.] ionizing a
`feed gas to generate
`a weakly-ionized
`plasma proximate to
`a sputtering target;
`
`Wang in view of Kudryavtsev and Yamaguchi
`
`The combination of Wang and Kudryavtsev discloses a method of
`generating sputtering flux.
`
`Wang at Title (“Pulsed sputtering with a small rotating magnetron.”).
`
`The combination of Wang and Kudryavtsev discloses ionizing a feed
`gas to generate a weakly-ionized plasma proximate to a sputtering
`target.
`
`Wang at Fig. 1
`
`Wang at 4:5-6 (“A sputter working gas such as argon is supplied from a
`gas source 32….”).
`
`Wang at 4:20-21 (“… a reactive gas, for example nitrogen is supplied
`to the processing space 22….”).
`
`Wang at 7:17-31 (“The background power level PB is chosen to exceed
`the minimum power necessary to support a plasma... [T]he application
`of the high peak power PP quickly causes the already existing plasma to
`spread and increases the density of the plasma.”)
`
`Wang at 7:19-25 (“Preferably, the peak power PP is at least 10 times the
`background power PB … and most preferably 1000 times to achieve the
`greatest effect of the invention. A background power PB of 1 kW
`[causes] little if any actual sputter deposition.”)
`
`Wang at 4:23-31 (“A small rotatable magnetron 40 is thus creating a
`region 42 of a high-density plasma (HDP)…”)
`
`[20b.] generating a
`magnetic field
`proximate to the
`
`The combination of Wang and Kudryavtsev discloses generating a
`magnetic field proximate to the weakly-ionized plasma, the magnetic
`field substantially trapping electrons in the weakly-ionized plasma
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`EXHIBIT A.12
`U.S. Patent No. 7,147,759
`
`Claim 38
`
`weakly-ionized
`plasma, the
`magnetic field
`substantially
`trapping electrons in
`the weakly-ionized
`plasma proximate to
`the sputtering target;
`and
`
`Wang in view of Kudryavtsev and Yamaguchi
`
`proximate to the sputtering target.
`
`‘759 Patent at 3:10-12 (“FIG. 1 shows a cross-sectional view of a
`known magnetron sputtering apparatus 100…” that has a magnet 126.”)
`
`‘759 Patent at 4:4-10 [describing the prior art Fig. 1] (“The electrons,
`which cause ionization, are generally confined by the magnetic fields
`produced by the magnet 126. The magnetic confinement is strongest in
`a confinement region 142….”)
`
`Wang at Fig. 1.
`
`Wang at 4:23-27 (“A small rotatable magnetron 40 is disposed in the
`back of the target 14 to create a magnetic field near the face of the
`target 14 which traps electrons from the plasma to increase the electron
`density.”)
`The combination of Wang and Kudryavtsev discloses applying a
`voltage pulse to the weakly-ionized plasma, an amplitude and a rise
`time of the voltage pulse being chosen to increase an excitation rate of
`ground state atoms that are present in the weakly-ionized plasma to
`create a multi-step ionization process that generates a strongly-ionized
`plasma, which comprises ions that sputter target material, from the
`weakly-ionized plasma, the multi-step ionization process comprising
`exciting the ground state atoms to generate excited atoms, and then
`ionizing the excited atoms within the weakly-ionized plasma without
`forming an arc discharge.
`
`‘759 Patent at Fig. 5
`Wang at Figs. 6, 7.
`
`Wang at 7:61-62 (“The pulsed DC power supply 80 produces a train of
`negative voltage pulses.”).
`
`[20c.] applying a
`voltage pulse to the
`weakly-ionized
`plasma, an
`amplitude and a rise
`time of the voltage
`pulse being chosen
`to increase an
`excitation rate of
`ground state atoms
`that are present in
`the weakly-ionized
`plasma to create a
`multi-step ionization
`process that
`generates a strongly-
`ionized plasma,
`which comprises
`ions that sputter
`target material, from
`the weakly-ionized
`plasma, the multi-
`step ionization
`process comprising
`exciting the ground
`state atoms to
`generate excited
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`Claim 38
`
`atoms, and then
`ionizing the excited
`atoms within the
`weakly-ionized
`plasma without
`forming an arc
`discharge.
`
`EXHIBIT A.12
`U.S. Patent No. 7,147,759
`
`Wang in view of Kudryavtsev and Yamaguchi
`
`Wang at 5:23-27 (“[The pulse’s] exact shape depends on the design of
`the pulsed DC power supply 80, and significant rise times and fall
`times are expected.”).
`
`Wang at 4:29-31 (“increases the sputtering rate...”).
`
`Wang at 7:19-25 (“Preferably, the peak power level PP is at least 10
`times the background power level PB, … most preferably 1000 times to
`achieve the greatest effects of the invention. A background power PB
`of 1 kW will typically be sufficient…”)
`
`Wang at 7:31-39 (“The SIP reactor is advantageous for a low-power,
`low-pressure background period since the small rotating SIP magnetron
`can maintain a plasma at a lower power and lower pressure than can a
`larger stationary magnetron. However, it is possible to combine highly
`ionized sputtering during the pulses With significant neutral sputtering
`during the back ground period.”).
`
`Wang at 7:3-6 (“Plasma ignition, particularly in plasma sputter
`reactors, has a tendency to generate particles during the initial arcing,
`which may dislodge large particles from the target or chamber.”)
`
`Wang at 7:47-49 (“The initial plasma ignition needs be performed only
`once and at much lower power levels so that particulates produced by
`arcing are much reduced.”).
`
`Wang at 7:13-28 (“Accordingly, it is advantageous to use a target
`power waveform illustrated in FIG. 6… As a result, once the plasma
`has been ignited at the beginning of sputtering prior to the illustrated
`waveform…”).
`
`Kudryavtsev at 34, right col, ¶ 4 (“Since the effects studied in this work
`are characteristic of ionization whenever a field is suddenly applied to a
`weakly ionized gas, they must be allowed for when studying emission
`mechanisms in pulsed gas lasers, gas breakdown, laser sparks, etc.”)
`
`Kudryavtsev at Fig. 1
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`EXHIBIT A.12
`U.S. Patent No. 7,147,759
`
`Claim 38
`
`Wang in view of Kudryavtsev and Yamaguchi
`
`Kudryavtsev at Fig. 6
`
`Kudryavtsev at 31, right col, ¶ 7 (“The behavior of the increase in ne
`with time thus enables us to arbitrarily divide the ionization process
`into two stages, which we will call the slow and fast growth stages.
`Fig. 1 illustrates the relationships between the main electron currents in
`terms of the atomic energy levels during the slow and fast stages.”).
`
`Kudryavtsev at 31, right col, ¶ 6 (“For nearly stationary n2 [excited
`atom density] values … there is an explosive increase in ne [plasma
`density]. The subsequent increase in ne then reaches its maximum
`value, equal to the rate of excitation [equation omitted], which is
`several orders of magnitude greater than the ionization rate during the
`initial stage.”)
`
`Kudryavtsev at Abstract (“[I]n a pulsed inert-gas discharge plasma at
`moderate pressures… [i]t is shown that the electron density increases
`explosively in time due to accumulation of atoms in the lowest excited
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`EXHIBIT A.12
`U.S. Patent No. 7,147,759
`
`Claim 38
`
`Wang in view of Kudryavtsev and Yamaguchi
`
`states.”)
`
`If one of ordinary skill, applying Wang’s power levels did not
`experience Kudryavtsev’s “explosive increase” in plasma density, it
`would have been obvious to adjust the operating parameters, e.g.,
`increase the pulse length and/or pressure, so as to trigger Kudryavtsev’s
`fast stage of ionization. One of ordinary skill would have been
`motivated to use Kudryavtsev’s fast stage of ionization in Wang so as
`to increase plasma density and thereby increase the sputtering rate.
`Further, use of Kudryavtsev’s fast stage in Wang would have been a
`combination of old elements that yielded predictable results of
`increasing plasma density and multi-step ionization.
`
`Kudryavtsev states, “[s]ince the effects studied in this work are
`characteristic of ionization whenever a field is suddenly applied to a
`weakly ionized gas, they must be allowed for when studying emission
`mechanisms in pulsed gas lasers, gas breakdown, laser sparks, etc.”
`Kudryavtsev at 34, right col, ¶ 4 (Ex. 1004). Because Wang applies
`voltage pulses that “suddenly generate an electric field,” one of
`ordinary skill reading Wang would have been motivated to consider
`Kudryavtsev and to use Kudryavtsev’s fast stage in Wang.
`
`The combination of Wang with Kudryavtsev and Yamaguchi discloses
`ionizing the feed gas comprises exposing the feed gas to an electrode
`that is adapted to emit electrons.
`
`See evidence cited in claim 20.
`
`Wang at 1:6-8 (“…the invention relates to sputtering apparatus and a
`method capable of producing a high fraction of ionized sputter
`particles.”).
`
`Wang at 1:25-29 (“…the positively charged sputtered ions can be
`accelerated towards a negatively charged wafer and reach deep into
`high aspect-ratio holes.”).
`
`Yamaguchi at ¶ [0027] (“introducing … a sputtering discharge gas,
`such as a rare gas…at the center of an ionizing space.”)
`
`Yamaguchi at ¶ [0027] (emphasis added) (“The ionizing mechanism 6,
`which is of a hot cathode type using Penning ionization, ionizes
`sputtering ions by hitting thermoelectrons, emitted from a hot electrode
`against ... sputtering discharge gas particles…”)
`
`38. The method of
`claim 20 wherein
`the ionizing the feed
`gas comprises
`exposing the feed
`gas to an electrode
`that is adapted to
`emit electrons.
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`EXHIBIT A.12
`U.S. Patent No. 7,147,759
`
`Claim 38
`
`Wang in view of Kudryavtsev and Yamaguchi
`
`Yamaguchi at ¶¶ [0012]-[0013]. (“It is an object of the present
`invention … to form a film at a high bottom coverage ratio…”; “It is
`another object of the present invention to provide a film forming
`method…and apparatus which can prevent substrate temperature from
`increasing.”)
`
`Yamaguchi at ¶ [0012] (“It is an object of the present invention…to
`form a film at a high bottom coverage ratio even on a substrate with
`deep grooves on its surface.”).
`
`Yamaguchi at ¶ [0015] (“These objects are attained by…ionizing
`sputtering particles…”).
`
`It would have been obvious for one of ordinary skill to combine the
`heated electrodes of Yamaguchi in the sputtering device of Wang.
`Both Wang and Yamaguchi relate to sputtering devices where
`ionization of the sputtered target material is carried out to achieve
`improved deposition in deep holes or grooves. Wang at 1:6-8 (“…the
`invention relates to sputtering apparatus and a method capable of
`producing a high fraction of ionized sputter particles.”); Wang at 1:25-
`29 (“…the positively charged sputtered ions can be accelerated towards
`a negatively charged wafer and reach deep into high aspect-ratio
`holes.”); Yamaguchi at ¶ [0012] (“It is an object of the present
`invention…to form a film at a high bottom coverage ratio even on a
`substrate with deep grooves on its surface.”); Yamaguchi at ¶ [0015]
`(“These objects are attained by…ionizing sputtering particles…”). A
`combination of Yamaguchi’s heated electrodes that emit electrons in
`the sputtering device described by Wang would be a combination of
`known elements in which each element performed as expected.
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